A stent is a tubular implant which provides radial outwards support for the wall of a body conduit, e.g. a blood vessel, bile duct, an air conduit or an esophagus. The stent usually consists of the elastic material, e.g. a metal or metal alloy or a polymer and frequently has a mesh or network or spiral-type structure, with stents in the form of a metal mesh being the most widely used. The stent is introduced into the relevant body conduit with the aid of a catheter and once in place, is bought into adhesive contact with the wall of the body conduit. Stents are used in particular with blood vessels as endoluminal vessel prostheses in the vessel wall for artherosclerotic stenosis therapy.
Contracting the stent to make it easier to introduce into the body conduit, introducing it in the contracted state with the aid of a catheter into the relevant body conduit and expanding the stent there with a balloon end of the catheter or by self-expansion into an expanded diameter is known from DE 199 51 279 A. The use of the high-grade elastic nickel titanium alloy Nitinol as a stent material is additionally known from DE 199 51 279 A1.
The stent used in each case must be precisely tailored in its length and in its expansion diameter to the characteristics of the relevant body conduit, in order on the one hand to sufficiently expand this conduit or support it and on the other hand so as not to slip within the body conduit, without however exercising such high expansion forces on the wall of the relevant body conduct that the result is an undesirably great expansion of the body conduit or even an injury to it. It is also known from the previously mentioned DE 199 51 279 A1, in order to avoid expansion forces which are too high, to provide the stent body at least partly with a covering which essentially prevents the stent body expanding fully in the direction of its free diameter.
A device for producing a stent, especially one containing a polymer material, is known from DE 69202308 T2. The stent consists of a cylindrical body which, when positioned at the desired location in the body conduit, can be expanded radially so that it delimits a hollow cylindrical cavity. This cylindrical body is filled before being used in the body conduit with a material which can be hardened so that after its radial expansion the device is hardened.